Airspace through which aircraft travel is divided into three-dimensional regional zones or sectors known as ATC sectors. The boundaries of the ATC sectors are determined laterally by latitudinal and longitudinal coordinates. The boundaries are determined vertically by the designation of specific altitudes as the lower limit (or base) and upper limit (or top) of a particular ATC sector. Further, each ATC sector is typically assigned a set of permanent communication frequencies in both the very-high frequency (VHF) range and the ultra-high frequency (UHF) range. ATC controllers use these frequencies to maintain voice contact with aircraft crews. In this manner, the ATC controllers maintain control over the aircraft with respect to ATC directions and clearances.
As an aircraft passes from one ATC sector to the next, an ATC controller will direct a frequency change from the current sector frequency to the frequency of the upcoming ATC sector via a verbal exchange with the pilot. In other words, the ATC controller for the sector that the aircraft has been in informs the pilot that he is about to enter into the next ATC sector and he (the pilot) is to tune his radio to the frequency for the next ATC sector. With conventional aircraft radios, in order to do this, the pilot must direct the majority of his attention to the radio control head and through a series of manual radio control manipulations, switch radio frequencies and initiate verbal contact with the new sector's controller. This series of events is necessary for every frequency change. Each time, it diverts the pilots attention from other more important duties, two of the most important being: 1) flying the aircraft and 2) looking outside of the aircraft for conflicting aircraft traffic. Being able to do neither of these tasks efficiently during the course of every frequency change is a significant detriment to the safest possible operation of the aircraft. This prior-art methodology, partially as a result of the limitations listed below, continually results in or contributes to the following: (1) mis-selection of frequencies, (2) exceptional amounts of pilot heads down time (i.e. time spent concentrating on items inside of the cockpit, not outside), continual frequency confirmation callbacks to ATC controllers, and pilot and ATC controller fatigue. These limitations of voice commanded frequency changes include, but are not limited to: (1) blocked frequency transmissions, (2) poor reception quality, (3) poor transmission quality, (4) poor enunciation, (5) distracting background noise, and (6) clipped or cut off radio transmissions. This methodology is also totally dependent upon voice transmission and reception, with no other sensory aid whatsoever. Further, the notice to change frequencies directed by the ATC controller is usually entirely unexpected and random in nature as the pilots have no defined way of knowing exactly where the ATC sector (regional block) boundries are located. These frequency changes take place, on average, nearly nine times during every flight hour on jet aircraft. Each change takes nearly ten seconds and eight radio control manipulations to complete, from the time the aircraft leaves parking on the ground until its return to parking after the flight segment. Therefore, it is plain to see this problem is a continual, repetitive, and distracting one that affects flight deck workload, continuity, and flight safety.
An additional related frequency change problem occurs each time an aircraft begins the standard sequence of events to leave the originating airport. It occurs to some extent with those aircraft operating under visual flight rules (VFR). It occurs to a great extent with aircraft operating on an instrument flight rules (IFR) flight plan. The crew must in nearly every instance contact, in order, air terminal information service (ATIS), clearance delivery (CLNC.), ground control (GND.), tower control (TWR.), and in initial flight just after departure, departure control (DEP.). The prior-art methodology necessary for this series of events requires the crew to reference on board publications to identify every one of the above discreet frequencies, and then manually tune in each of the frequencies as they are needed during ground operation. Again, this a continual, repetitive, and distracting problem affecting flight deck workload, continuity, and ultimately flight safety.
A principal object of the present invention is to provide a touch operated control and, alternatively, an automatic control, for tuning a communication radio to each new frequency, to eliminate the above discussed problems experienced when using the prior-art methodology.
The invention has particular use where the vehicle is an aircraft. It is believed, however, that the invention is not limited to aircraft use but has a more general application.